001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.expression.spel.ast;
018
019import org.springframework.expression.AccessException;
020import org.springframework.expression.BeanResolver;
021import org.springframework.expression.EvaluationException;
022import org.springframework.expression.TypedValue;
023import org.springframework.expression.spel.ExpressionState;
024import org.springframework.expression.spel.SpelEvaluationException;
025import org.springframework.expression.spel.SpelMessage;
026
027/**
028 * Represents a bean reference to a type, for example <tt>@foo</tt> or <tt>@'foo.bar'</tt>.
029 * For a FactoryBean the syntax <tt>&foo</tt> can be used to access the factory itself.
030 * 
031 * @author Andy Clement
032 */
033public class BeanReference extends SpelNodeImpl {
034
035        private final static String FACTORY_BEAN_PREFIX = "&";
036        
037        private final String beanName;
038
039
040        public BeanReference(int pos, String beanName) {
041                super(pos);
042                this.beanName = beanName;
043        }
044
045
046        @Override
047        public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
048                BeanResolver beanResolver = state.getEvaluationContext().getBeanResolver();
049                if (beanResolver == null) {
050                        throw new SpelEvaluationException(
051                                        getStartPosition(), SpelMessage.NO_BEAN_RESOLVER_REGISTERED, this.beanName);
052                }
053
054                try {
055                        return new TypedValue(beanResolver.resolve(state.getEvaluationContext(), this.beanName));
056                }
057                catch (AccessException ex) {
058                        throw new SpelEvaluationException(getStartPosition(), ex, SpelMessage.EXCEPTION_DURING_BEAN_RESOLUTION,
059                                this.beanName, ex.getMessage());
060                }
061        }
062
063        @Override
064        public String toStringAST() {
065                StringBuilder sb = new StringBuilder();
066                if (!this.beanName.startsWith(FACTORY_BEAN_PREFIX)) {
067                        sb.append("@");
068                }
069                if (!this.beanName.contains(".")) {
070                        sb.append(this.beanName);
071                }
072                else {
073                        sb.append("'").append(this.beanName).append("'");
074                }
075                return sb.toString();
076        }
077
078}